When mine humps I smack my hands together or tell him "NO" in a firm voice. Then I call him over to me and change his mind about it...hes really bad about humping my other dog, but not where he should, just on her head or leg...the little weirdo!
But anytime he gets nippy I tell him no, and then put my finger on his nose. He hasnt done it since he was a puppy and I made sure to stop that habit before it got bad.
__________________  Rebecca  Joey  Carley |